Quinolones (Includes Levaquin) ↔ Cns Disorders

Severe Potential Hazard, Moderate plausibility

Applies to: CNS Disorder

Quinolones may cause CNS stimulation manifested as tremors, agitation, restlessness, anxiety, confusion, hallucinations, paranoia, insomnia, toxic psychosis, and/or seizures. Benign intracranial hypertension has also been reported. Therapy with quinolones should be administered cautiously in patients with or predisposed to seizures or other CNS abnormalities. In addition, these patients should be advised to avoid the consumption of caffeine-containing products during therapy with some quinolones, most notably ciprofloxacin, enoxacin, and cinoxacin, since these agents can substantially reduce the clearance of caffeine and other methylxanthines, potentially resulting in severe CNS reactions.

Quinolones have been reported to prolong the QT interval of the electrocardiogram in some patients. QT prolongation may potentiate the risk of ventricular arrhythmias including ventricular tachycardia, ventricular fibrillation, and torsade de pointes. The risk appears to be greatest with grepafloxacin and sparfloxacin (both are no longer marketed in the U.S.), although cardiovascular morbidity and mortality attributable to QT prolongation have also been reported rarely with others like gatifloxacin, levofloxacin, ciprofloxacin, and ofloxacin. Reported cases have primarily occurred in patients with advanced age, cardiac disease, electrolyte disturbances, and/or underlying medical problems for which they were receiving concomitant medications known to prolong the QT interval. Therapy with quinolones should be avoided in patients with known QT prolongation and/or uncorrected electrolyte disorders (hypokalemia or hypomagnesemia) and in patients treated concomitantly with class IA or III antiarrhythmic agents. Cautious use with ECG monitoring is advised in patients with other proarrhythmic conditions such as clinically significant bradycardia, congestive heart failure, acute myocardial ischemia, and atrial fibrillation. As QT prolongation may be a concentration-dependent effect, it is important that the recommended dosages or infusion rates of these drugs not be exceeded, particularly in patients with renal and/or hepatic impairment.

Antibiotics (Includes Levaquin) ↔ Colitis

Moderate Potential Hazard, Moderate plausibility

Applies to: Colitis/Enteritis (Noninfectious)

Pseudomembranous colitis has been reported with most antibacterial agents and may range in severity from mild to life-threatening, with an onset of up to two months following cessation of therapy. Antibiotic therapy can alter the normal flora of the colon and permit overgrowth of Clostridium difficile, whose toxin is believed to be a primary cause of antibiotic-associated colitis. The colitis is usually characterized by severe, persistent diarrhea and severe abdominal cramps, and may be associated with the passage of blood and mucus. The most common culprits are clindamycin, lincomycin, the aminopenicillins (amoxicillin, ampicillin), and the cephalosporins. Therapy with broad-spectrum antibiotics and other agents with significant antibacterial activity should be administered cautiously in patients with a history of gastrointestinal diseases, particularly colitis. There is some evidence that pseudomembranous colitis, if it occurs, may run a more severe course in these patients and that it may be associated with flares in their underlying disease activity. The offending antibiotic(s) should be discontinued if significant diarrhea occurs during therapy. Stool cultures for Clostridium difficile and stool assay for C. difficile toxin may be helpful diagnostically. A large bowel endoscopy may be considered to establish a definitive diagnosis in cases of severe diarrhea.

Quinolones (Includes Levaquin) ↔ Crystalluria

Moderate Potential Hazard, Moderate plausibility

Applies to: Dehydration, Diarrhea, Vomiting

Crystalluria has been reported rarely during quinolone therapy. Although it is not expected to occur under normal circumstances with usual recommended dosages, patients who are dehydrated (e.g., due to severe diarrhea or vomiting) may be at increased risk and should be encouraged to consume additional amounts of liquid or given intravenous fluid to ensure an adequate urinary output. Alkalinity of the urine should be avoided, since it may also increase the risk of crystalluria. Renal function tests should be performed periodically during prolonged therapy (> 2 weeks).

Quinolones (Includes Levaquin) ↔ Diabetes

Moderate Potential Hazard, Moderate plausibility

Applies to: Diabetes Mellitus

The use of certain quinolones such as clinafloxacin, gatifloxacin, temafloxacin, levofloxacin, and moxifloxacin has been associated with disturbances in blood glucose homeostasis possibly stemming from effects on pancreatic beta cell ATP-sensitive potassium channels that regulate insulin secretion. Hypoglycemia and, less frequently, hyperglycemia have been reported, although the latter may also occur due to infection alone. Hypoglycemia has usually occurred in patients with diabetes receiving concomitant oral hypoglycemic agents and/or insulin. Administration of ciprofloxacin, levofloxacin, norfloxacin, and especially gatifloxacin in patients treated with sulfonylureas or other oral hypoglycemic agents has resulted in severe, refractory hypoglycemia and hypoglycemic coma. Elderly patients and patients with reduced renal function are particularly susceptible. Blood glucose should be monitored more closely whenever quinolones are prescribed to patients with diabetes. Gatifloxacin has been known to cause hypoglycemic episodes generally within the first 3 days of therapy and sometimes even after the first dose, while hyperglycemia usually occurs 4 to 10 days after initiation of therapy. Patients should be counseled to recognize symptoms of hypoglycemia such as headache, dizziness, drowsiness, nausea, tremor, weakness, hunger, excessive perspiration, and palpitations. If hypo- or hyperglycemia occur during quinolone therapy, patients should initiate appropriate remedial therapy immediately, discontinue the antibiotic, and contact their physician.

Quinolones (Includes Levaquin) ↔ Renal Dysfunction

Moderate Potential Hazard, High plausibility

Applies to: Renal Dysfunction

Quinolones (except trovafloxacin, moxifloxacin, and nalidixic acid) and their metabolites are eliminated by the kidney. Patients with renal impairment may be at greater risk for adverse effects from quinolones, including nephrotoxicity, due to decreased drug clearance. Dosage adjustments may be necessary and modifications should be based on the degree of renal impairment and severity of infection in accordance with the individual product package labeling. Renal function tests should be performed periodically during therapy.

Do not stop taking any medications without consulting your healthcare provider.

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